KR20230006559A - Modeling compound and manufacturing method thereof - Google Patents

Abstract

The present invention consists of at least a binder and a softener, the binder and the softener are in the form of a plastisol, the plastisol consisting essentially of PVC and a softener, the mass being 32 to 60% by weight of the total softener have content

Description

Modeling compound and manufacturing method thereof

The present invention relates to oven-hardenable modeling compounds and methods of making such modeling compounds.

Oven-curable compounds of plastics for molding and modeling objects are known in principle.

Modeling compounds are also understood to mean polymer clays in the case of so-called clays or polymer-containing compounds.

DE 25 15 757 C3 discloses plastic compounds which can be deformed by hand and hardened by heating.

These compounds consist essentially of polyvinyl chloride (PVC), a filler and a phthalate-containing plasticizer.

DE 10 2005 059 143 A1 also discloses modeling compounds free of phthalate-containing plasticizers.

A disadvantage of these compounds according to the prior art is that they are not resistant to aging and the blocks of modeling compounds show an increase in hardness after long-term storage, even in unopened packaging. As a result, the modeling compound is difficult for a user to knead.

This still represents an ideal case for aging, since long storage times may result in modeling blocks that can no longer be hand-kneaded, and may even become unusable.

This is due to the fact that the plasticizers in the compound exhibit interactions already at room temperature. This is referred to as the aging process of an uncured PVC-containing modeling compound.

In the case of the modeling compound according to the prior art, the powdery raw material is mixed with a plasticizer at a temperature of 20° C. to 30° C. A plasticizer absorption of 25 to 30% by weight is achieved. Individual PVC agglomerates disintegrate over time, for example during longer storage, which in turn creates the need for plasticizers because the surface of the PVC grains has increased.

In this case, the pre-stored plasticizer in the intermediate space between the PVC particles, which is mainly responsible for the smooth kneading behavior of the modeling compound, no longer exists. Instead, the plasticizer accumulates on the newly formed surface of the disintegrated aggregates. The hardness of an uncured modeling compound increases over time as a result of this phenomenon.

It is therefore an object of the present invention to produce a modeling or molding compound that does not have the above-mentioned disadvantages and to minimize the aging process, in particular during storage of PVC-containing modeling compounds in an uncured state, thereby ensuring greater storage stability.

A further object of the present invention is to increase the flexibility of the modeling compound after bake hardening and optionally to improve the transparency of the cured compound to glass transparency.

It is also an object of the present invention to provide a method capable of preparing such a compound.

This object is achieved with the features contained in claims 1 and 9.

Advantageous improvements and developments of the compounds according to the invention are covered in further claims.

The oven-curable modeling compound according to the present invention consists of at least a binder and a plasticizer, the binder being present as a plastisol, the plastisol comprising substantially PVC and a plasticizer, and optionally other supplements and/or additives. . The modeling compound may include, for example, at least one filler as a further supplement and/or additive.

A modelable compound exists when the content of the plasticizer in the mixture is adjusted so that the plasticizer attaches itself to the surface of the PVC particles and is stored as a content in the intermediate space between the solid particles to form a kneadable resistance. If the plasticizer content is too low, that is, if the plasticizer does not exist even in the interspace and accumulates only on the surface of the solid particles, the compound is too hard or very difficult to knead.

On the other hand, if the surfaces of the solid particles and the intermediate spaces between the solid particles are completely covered with the plasticizer or even supersaturated, the resulting modeling compound will flow too much and can no longer be modeled.

Heat must now be supplied to transform the modeled materials and objects into a permanent solid state. This is so-called bake hardening. The plasticizer or plasticizer content is responsible for the curing process, which causes the compound to cure due to its interaction with the PVC.

However, plasticizers have been shown to have a certain affinity for PVC granules or PVC solid particles, even when stored at room temperature, allowing the PVC granules, which are partially composed of agglomerates, to break down and create a new surface/surface area. The plasticizer stored in the intermediate space migrates through the newly created surface to the newly created surface. As a result, the hardness of the modeling compound increases because the formability decreases due to the lack of the liquid plasticizer component in the intermediate space.

A particular advantage of the compound according to the invention is that the disintegration of the agglomerates (= aging process) can proceed in the production process using the method according to the invention at higher temperatures and by mixing with higher amounts of plasticizer.

This ultimately improves the storage stability or increase in hardness of uncured compounds over time, for example by adding plasticizers in a targeted manner after the "aging process during the manufacturing process" has been initiated.

An additional benefit resulting from the increased proportion/content of plasticizer in the modeling compound is that the system's ability to gel is improved during the curing process, resulting in greater elasticity after bake curing. Surprisingly, it has been shown that the transparency after bake curing can be significantly increased by mixing at higher temperatures and associated plasticizer contents and by reducing the use of fillers and/or additives.

The binder used, essentially in the form of PVC, and the added plasticizer form the plastisol. The PVC may in particular be present as emulsion PVC, suspension PVC and microbead suspension PVC or mixtures of the individual PVC types, with or without emulsifiers.

Phthalate-free and/or phthalate-containing plasticizers may be used as plasticizers.

The total plasticizer content is from 32 to 60% by weight, in a preferred embodiment from 35 to 55% by weight, and in a particularly preferred embodiment from 38 to 52% by weight.

Phthalate-free plasticizers are based on citric acid, adipic acid and/or benzoate esters.

Phthalate-free plasticizers include, for example, acetyl tributyl citrate, tri(2-ethylhexyl) acetyl citrate, trioctyl citrate, tridecyl citrate, tributyl citrate, trihexyl citrate, triethyl citrate rate, dioctyl adipate, diisodecyl adipate, diisononyl adipate, bis(2-ethylhexyl) adipate, diisononyl 1,2-cyclohexanedicarboxylate, acetic acid esters of monoglycerides, benzo ates or mixtures of at least two of the foregoing substances. Plasticizers may further belong to the group of benzoates or benzoate esters. 2,2,4-triethyl-1,3-pentanediyl dibenzoate and its derivatives, triethylene glycol dibenzoate, diethylene glycol dibenzoate, diethylene glycol monobenzoate and/or propylene glycol dibenzoate thereof Eight is mentioned as an example. Any mixtures of all plasticizers mentioned above are possible.

Examples of phthalate-containing plasticizers are di-2-ethylhexyl phthalate, ditridecyl phthalate and dibutyl phthalate.

Any mixture of phthalate-containing plasticizers is possible.

It is also possible to use mixtures of plasticizers consisting of phthalate-free and phthalate-containing plasticizers.

A particularly preferred embodiment of the present invention is a compound that does not contain phthalate-containing plasticizers.

Stabilizers improve PVC stability. That is, the stabilizer prevents the dissociation of hydrogen chloride in particular. Among other things, inorganic and organic salts of calcium, zinc, tin, magnesium, sodium, potassium metals, for example calcium stearate, sodium stearate, potassium stearate, zinc stearate, magnesium stearate, tin stearate and/or or mixtures of metal salts are used for this purpose.

Inorganic and/or organic fillers having a particle size of <250 μm, preferably less than 100 μm, such as kaolin, chalk, silica, talc, aluminum hydroxide and/or powdered clay, are practically used as fillers.

Metal glitter, glitter powder and glitter flakes or mixtures of these substances may be present as additional fillers, for example to achieve special optical effects.

So-called lightweight fillers can also be used as fillers, or the other fillers mentioned can be mixed. Examples of lightweight fillers are hollow spheres, in particular hollow glass microspheres, for example from 3M or Lehmann & Voss. Depending on the content of the lightweight filler, the desired density can advantageously be set in the range from 0.3 to 1.1 g/ml. The size of the commercially available lightweight filler can also be chosen freely, and its size preferably ranges from 10 to 400 μm.

In addition, fillers based on polymers can also be used. PAMA, PMMA and/or polyethylene are named examples of this group.

The pigments may be present as colorants in pure form as powder pigments, preferably azo-free color pigments, effect pigments and/or azo-free coating dyes. A number of possible color pigments include: Pigment Yellow 14 (C.I. 21095), Pigment Red 254 (C.I. 56110), Pigment Orange 34 (C.I. 21110), Pigment Red 122 (C.I. 73915), Pigment Green 7 (C.I. 74260), Pigment White 6 (C.I. 77891), Pigment Black 7 ( Pigment Black 7) (C.I. 77266), Pigment Red 101 (C.I. 77491), Pigment Violet 23 (C.I. 51319), Pigment Blue 29 (C.I. 77007) , Pigment Yellow 185 (C.I. 56290), Pigment Yellow 1 (C.I. 11680), Pigment Red 48:2 (C.I. 15865:2), Pigment Pigment Red 53:1 (C.I. 15585:1), Pigment Orange 34 (C.I. 21115), Pigment Yellow 83 (C.I. 21108) and Pigment Blue 15 (Pigment Blue 15) (C.I. 74160).

The addition of these colorants gives the modeling compound a colorful appearance.

Pearlescent pigments, mica iron metallic luster pigments, polyester glitter pigments and luminescent pigments may be specified as additional colorants.

Here, it can be seen that kneading compounds of different colors can also be blended, mixed or kneaded with each other as desired to cause a marbling effect.

The invention will be illustrated in more detail using framework examples and some formulation examples.

Framework Example 1

20 - 68% binder by weight

32 - 60% plasticizer by weight

0 - 40% filler by weight

0 - 20% by weight of other additives

Framework Example 2 - Preferred Compositions

40 - 68% binder by weight

35 - 55% plasticizer by weight

0 - 20% by weight filler

0 - 20% by weight of other additives

Framework Example 3 - Particularly Preferred Compositions

45 - 63% binder by weight

38 - 52% plasticizer by weight

0 - 17% filler by weight

0 - 15% by weight of other additives

Stabilizers, co-stabilizers, colorants and/or fillers are examples of other additives that may be used.

Formulation Example 1 - Yellow Modeling Compound

51% by weight E-PVC and S-PVC

Plasticizer based on 42% by weight of ATBC

6% by weight stabilizer

0.5% by weight filler

0.5% by weight of Pigment Yellow 83

Formulation Example 2 - Transparent modeling compound after curing

48% by weight of E-PVC and S-PVC

Plasticizer based on 52% by weight of ATBC

Prior art - comparative formulation according to DE 10 2005 059 143

59% PVC by weight

Plasticizer based on 24% by weight of citric acid

1% by weight stabilizer

7% by weight co-stabilizer

4% filler by weight

1% Pigment Red 254 by weight

The phthalate-free plasticizers preferably used are based on citric acid and/or adipic acid.

The desired concentration of the compound can be readily adjusted by varying the binder content and/or plasticizer content.

The present invention will be illustrated in more detail using the table below.

Table 1: Hardness increase of uncured compounds as a function of time at 40 °C.

Compared to the prior art, compounds that had not yet been cured in the oven according to the application literature had a significantly lower increase in hardness when stored at 40 °C over time (30 or 90 days), as shown in Table 1. .

Table 2: Flexibility of Cured Compounds

This higher breaking strength can be determined and confirmed with a “texture analyzer”. A round fracture bar with a length of 10 cm and a diameter of 1 cm was prepared as a test specimen.

The method according to the invention for producing such a modeling compound is described below.

The background of the process according to the invention is that the mixing process of the individual components of the compound takes place at an elevated temperature of about 55°C to 70°C, preferably about 58°C to 65°C. As a result, agglomerate disintegration is initiated during the mixing process, as a result of which an increased content of plasticizer is added or may be added to the PVC in the solid phase. More plasticizer can be added/introduced during the mixing process because of the initial creation of new surfaces due to agglomerate disintegration.

A method/process for preparing a compound according to the present invention may be described as follows.

In this process, a quantity of PVC powder and plasticizer are added in a mixing process at a mixing temperature of about 55° C. to 70° C. along with any other supplements and/or additives.

In the above method, the components of the compound are

20 - 68% by weight binder;

32 - 60% plasticizer by weight,

0 - 40% by weight of a filler and

0 - 20% by weight of other additives.

Preferred components of the compound in the method are

40 - 68% by weight binder,

35 - 55% plasticizer by weight,

0 - 40% by weight of a filler and

0 - 20% by weight of other additives.

The most preferred component of the compound in the method is

45 - 63% binder by weight

38 - 52% plasticizer by weight

0 - 17% filler by weight

0 - 15% by weight of other additives.

By accepting/introducing higher amounts of plasticizer into the PVC system of the modeling compound, the increase in hardness of the modeling compound is reduced over time, significantly improving storage stability.

Surprisingly, it has been found that the more plasticizer added to the PVC powder, the higher the resulting flexibility of the compound after the curing process. The higher plasticizer content significantly/significantly increases the flexibility of the cured compound.

It has also surprisingly been shown that higher transparency can also be achieved with the method according to the invention.

The composition according to the invention is used in the manufacture of plastics, manually deformable and heat-setting compounds as modeling compounds for use by children and for the manufacture of crafts and/or industrial objects and products made therefrom, such as seals and ornaments.

Compounds or modeling compounds are additionally used for therapeutic purposes in the medical field to train and rehabilitate tactile abilities.

Articles and objects made from compositions according to the present invention are cured by the action of heat after molding to form articles and objects.

Claims (10)

An oven-hardenable modeling compound consisting of at least a binder and a plasticizer, wherein the binder and the plasticizer are in the form of a plastisol, the plastisol comprising substantially PVC and a plasticizer,
Characterized in that the compound has a total plasticizer content of 32 to 60%. 2. A compound according to claim 1 characterized in that the total plasticizer content is between 35 and 55 weight percent in a preferred embodiment. 3. Compound according to claim 1 or 2, characterized in that the plasticizer is formed as a phthalate-free and/or phthalate-containing plasticizer. 3. Compound according to claim 1 or 2, characterized in that the phthalate-free plasticizer is based on citric acid, adipic acid and/or benzoate esters. 4. The method according to claim 3, wherein the phthalate-free plasticizer preferably used is acetyl tributyl citrate, tri(2-ethylhexyl) acetyl citrate, trioctyl citrate, tridecyl citrate, tributyl citrate, trihexyl citrate. rate, triethyl citrate, dioctyl adipate, diisodecyl adipate, diisononyl adipate, diisononyl 1,2-cyclohexanedicarboxylate, acetic acid esters of monoglycerides, benzoates or any of the above Characterized in that it is a mixture of at least two of the compounds. 6. The method according to any one of claims 1 to 5, wherein the compound is at least
20 - 68% binder by weight
32 - 60% plasticizer by weight
0 - 40% filler by weight
0 - 20% by weight of other additives. 7. Compound according to any one of claims 1 to 6, characterized in that the filler is inorganic and/or organic. 8. Compound according to any one of claims 1 to 7, characterized in that the filler is kaolin, talc, chalk, silicic acid, aluminum hydroxide and/or powdered clay and/or lightweight filler. 9 . The colorant according to claim 1 , wherein the colorant is present as pigment, as powder pigment, preferably as azo-free color pigment, effect pigment and/or as azo-free laked dye. characterized by a compound. A method for producing the modeling compound according to claim 1 , wherein the method/process is wherein the amount of PVC powder and plasticizer is subjected to a mixing process along with any other supplements and/or additives, wherein the mixing process is performed at about 55° C. characterized in that it is designed to occur at a mixing temperature of from 70 ° C. to 70 ° C.